SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb6e867a0a5154cb031a32262ea113a502aa34d08b5710de7510ede1c0773901' 
  AND token = 'zbkZE1ejEH8P5IADHjtQxNOQfuv/3fUtPWBsJcilHgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}